Drafting implement



May 27, 1930.

T. P. LEAMAN DRAFT ING IMPLEMENT Filed 001;. 1l, 1927 l Trr 'zivil/fill,

Patented May 27, 1930 UNITED STATES THOMAS P. LEAMAN, F BRIDGEPORT, CONNECTICUT DRAFTING I-MPLEMENT Application led Gctober 11, 1927. Serial No. 225,483.

This invention relates to a drafting implement for use by draftsmen in making drawings, and partlcularly to an easily portable device for use in making sketches, and has for an object to provide a device of this character in which there is improved means for holding the paper upon which the sketchor drawing is to be made, which means w1ll securely clamp the paper in position and may be easily released for insertion or removal of the sheets of paper.

It is also an object of the invention to provide improved means for mounting the clamps which may be adjusted for properly aligning v the clamps so that they may be used as guides for straight-edge instruments.

It is a further object of the invention to provide an improved strengthening means for the base orbody of the board to prevent warping, but which will allow lateral expansion and contraction.

It is a still further'object of the inventio to provide an improvedstraight-edge instrument for use with this type of devices.

With the foregoing and other objects in view, I have devised the construction rillustrated in the accom anying drawing forming a art of this speci cation. In this drawing, ig. 1 is aperspective view of my improved so drafting implement looking down on the top of the same. 4

Fig. 2 is a detail section through one of the clamps and the means for mounting it on the base or board showing the clamp `in paper holding position. Fig. 3 is a similar section but showing the clamp raisedto released the paper. f

Fig. 4 is a detail section substantially on line 4-4 of Fig. 3 showing a plan View of the clamp securing means. l

Fig. 5 is a detail section of one end of the board showing the strengthening means, and

Fig. 6 is an improved straight edge instrument. v This implement is designed primarilyv as an easily portable device for carrying one or more sheets of paper on which the sketches or drawings may be made and in which the sheets of paper may be easily secured lor re- 5 leased, and whenc amped "to the boardv will be securely held in the proper position without shifting during the making of the drawing or sketches. The clamping means for the paper also comprise two elements arranged at right angles to each other along an end and one side edge of the sheets of paper so that the paper is properly held in position, and these clamps form guides for straight edge instruments used in making the drawings. It will, of course, however be understood that the subject matter of the invention'may be used on larger and less portable devices if desired. -In the structure shown the device comprises a base or board 10 of wood or other suitable material, usually wood, and has two clamps 11 for holding one or more sheets of paper 12 to the board. A con\ venient arrangement is to have the sheets of paper in a pad and clamp the entire pad on the board, the sheets being torn oif as used. It will be apparent from the drawing that these two clamps are mounted one adjacent one side edge of the board and the other ad- 'jacent an end ofthe board, it bein preferred that they be arranged at the left slde and top respectively. They are also arranged at right angles to each other and form guides for a straight-edge instrument, suchA as a triangle or the .special instrument 13 illustrated.

Each clamp 11 comprises) an elongated member preferably of sheet metal and substantially of inverted U-shape in cross section with its opposite edges 14 and 15 toward the surface of the board. Each member 11 is secured to 'theboard by a, pair of spring 85 hinges. These hinges comprise a flat strip of metal including a base portion 16 having an l elongated slot 17 and a tongue portion 18 bent backwardly over the basefportion and spaced above the same. This spring member is ysecured to the board 10 by means of a screw 19 passing through the board and accessible for operation at the lower side thereof and i threaded into a headed member 20 having 95 I clamp, so that they are independently adjust that it will be held against turning movements in the board. The head of the screw preferably seats in the head of a countersunk washer 22 recessed in the under side of the board. It will be apparent that by loosening the screw the spring' member 16-18 may be adjusted toward or from the edge of the board and then clamped in adjusted position by tightening the screw, and that each spring member is adjustable independently of the 'other so that the member 11 of the clamp may be arranged in proper alignment. It will, of course, be understood that in mounting the upper clamp or the clamp at the end of the board, the spring members 16-18 are arranged at right angles to those for the side able toward and frm the end of the board, and therefore, either clamp may be adjusted angularly with respect to the other clamp to ring their inner upright walls 23 at right angles to each other.

Each of the ba'r members l1 carries a pair of straps 211 of sheet metal which are riveted to the bar, as shown at 25, and are inclined and pass around theouter edge 14, as shown at 26. They also have an opening 27 for passage of a reduced extension 28 on the tongue 18 of the spring element, this opening being substantially the widthof this extension so that the shoulders 29 at the side of the extension will limit the amount towhich this' extension will project into the -1 opening. This extension is also preferably member as indicated in Fig. 2, the downward pull of the tongue 18 on the lower edge of the opening 1n the strap will tend to swing the clampA 11 to the right or clockwise about theouter edge 14 and will firmlyr clampv the inner edge 15 against the tpof the sheets Q`f paper 12` to clamp them against the top' surfaeeofthe board,

If it is desired to release these sheets of paper all that is neccessary is to swing the inner edge 15 rof the clamp upwardly or .counterclockwise, as viewer in Figs. 2 and 3.V The hook' extension 28 n the tongue. 18 vwill prevent the clamp moving outwardly, and although it swings about the outer edge 14 this edge will slide inwardly to the position shown inFig. 2 until the outer wall 30 of the bar rests on the top of the board or base portions 16 of the springs. It willnow be apparent that the downward pressure of the spring tongue 18 on the bottom of the opening in the strap 24 is outwardly of the edge 14 and will hold this clamp in the open position of Fig. 3. This will permit of easy insertion or removal of the sheets of paper ,without any interference from the spring sary is merely to swing the upper 'l'rcc edge 15 outwardly from the position of Fig. 3, as` indicated in dotted lines. This action will withdraw the hook extension 28 from the opening in the strap 24 and will release the .clamping bar 11. This structure, therefore,

is easily assembled and disassembled without the use of special tools, besides being of eX`- tremely simple construction.

It will, of course, be understood that the spring members 16-18 will be adjusted so that the inner upright walls 23 of the clamping bars 11 are at right angles to each other and these inner walls, therefore, may be used as guides for a straight-edge member 13 for drawing lines at right angles to each other when the bars 11 have been clamped onto the paper sheets 12. If one end of this member 13 is inclined, as indicated at 31, at an angle of sixty degrees to its adjacent side edge, then by placing this inclined edge against either of the guide bars 1 l lines at either sixty or thirty degrees to each of these bars may be drawn. If the other portion of this end .is inclined, as shown at 32, at forty-five degrecs to its adjacent side edge then by placing this inclined edge against the bars 11 lines at fortyfive degrees to these bars may be drawn. Therefore, this single instrument may be used for drawing horizontal and vertical lines and also lines at the three angles most commonly employed for drafting purposes.

Either one or both of the edges of the instrument 13 may be provided with. a scale 33 in inches or other units as desired, so that the use of a separate scale is unnecessary. The thumb openings 34 adjacent the opposite ends of this instrument make it convenient to hold it againstthe guides 23 by inserting the thumb in the nearest opening as the hand grips the edge of the board. This also facilitates shifting of the instrument along the guide. l. j

Asthe board 10 is made of wood it will, of course, tend to warp due to changes in moisture conditions, and will also tend to expand and"contractlaterally because of these eonditions'. I have provided improved means for preventing warping of theyboard while at the same time permitting lateral expansion and contraction. I have accomplished this by providing a dove-tail rib 35 along each end of the board and then slipping over this dove tail a similarly shaped metal bar 36, it being of course, understood that the dove-tail is inserted by sliding it longitudinally from one end of the bar. The har is then secured from the sliding off this board by a screw 37. It will be apparent that due to the shape of this bar it is very rigid and offers great resistance against lateral bending and will, therefore, hold the board from .Warping, but that the board is allowed" to expand and contract laterally as the dovetail end 35 will merely slide laterally in the channel of the bar 36.

It will be apparent from the foregoing description that the structure of this device is very simple and easily manipulated, that the clamps are easily adjustable so that they may be brought at an exact right angle to each other, and that they firmly clamp the papers to the board through the action of the springs 16-18, that When in the clamping position the clamping bars present a smooth outer surface so that they are not easily displaced or accidentally released while in use, but when it is desired to remove lor insert new sheets of paper the clamps may be easily manipulated for this purpose. Furthermore, in a portable device of this character especially where it is used to make sketches of machinery in a shop it is desirable that the number of instruments used be reduced to a minimum. Therefore, this arrangement of guides using the straight-edge instrument 13 shown reduces these instruments to a single member which will perform all the operations usually performed by separate scales, T-square and triangles.

Having thus set forth the nature of my invention, what I claim is:

1. In a drafting implement, a rectangular board member, means for clamping one or more sheets of paper to said board comprising a member extending longitudinally of an edge of the board, and springs carried by one of said members and ,connected to the other member to clamp said second member to the face of the board, said springs also forming the sole means for securing the second member yto the board', said second member having an upright inner wall forming a guide for straight-edge instruments.

2. In a drafting implement, a board, a clamp for clamping paper sheets to the'board including an inverted substantially U-shaped member, a pair of springs secured to the board and engaging said member and tending to hold the edges thereof againstthe surface of the board, said member being turnable about its outer edge as a pivot and its inner wall forming a guide for a straight-edge instrument.

3. In a drafting implement,`a board, a pair of clamps for a sheet of paper arranged one adjacent one side edge of the board and the other adjacent one end, a pair of securing vmeans for each clamp and at least onevof them being adjustable longitudinally of the other clamp so that the clamps may be setv at right angles to each other, each clamp being provided With an upright wall forming a guide for a straight-edge instrument.

4. In a drafting implement, a board, a pair of paper clamps including bars mounted 'on the board at substantially right angles to each other and having upright walls forming guides for straight-edge instruments, means for mounting said bars including springs tending t0 hold them against the board, one of said means being adjustable on the board transversely of its bar so that the bar may be adjusted angularly with respect to the other bar.

5. In a drafting implement, a paper clamp including a bar, a pair of securing means for said bar comprising a spring element having a base and a tongue portion extending outwardly over the base and tending to move toward the base, and means for securing the ybase to the board. said bar having means cooperating With said tongue whereby the bar is secured to and clamped against the board. 6. In a drafting implement, a board, a paper clamp mounted on said board including an inverted substantially U-shaped'bar, and spring operated means for securing said bar to the board comprising a spring member having a base and a tongue portion extending outwardly over the base, means for securing the base tothe board, and a strap extending between the outer upright wall of the bar and the body of the bar having an -v opening therein into which the end of the tongue projects to clamp the bar against the board.

7. In a drafting implement, a board, a paper clamp mounted on said board including a bar adapted to be turned about its outer edge, a securing means for the bar comprising a spring having a base provided with an elongated slot, a securing screw extending through said slot and adapted for manipulation to permit adjustment of said spring on the base, said spring also including a tongue portion extending outwardly over the base and tending to move toward the base. and means carried by the bar engaged by said tongue to clamp the bar to the board.

8. In a drafting implement, a board, a paper clamp on said board including an inverted substantially U-shaped bar adapted to turn about its outer edge, a pair of spring members for securing the bar'to the board comprising a base and a tongue extending outwardly over the base and having a hooked end, means for securing the base to the board, a strap carried by the bar and having an opening to receive said hooked end, said, opening being so located that when the bar is in the horizontal position the spring tongue will tend to clamp it against the board 1n j that position and when the betrv s turned about its outer edge to the upright position the opening will pass over this edge so that the spring will tend to hold the bar in the upright position.

In testimony whereof I ax my signature.

f THOMAS P. LEAMAN. 

